1. Field of the Invention
The present invention relates generally to pipeline pigs, and more particularly, but not by way of limitation, to an improved pipeline pig implement and apparatus for retaining same on a pipeline pig.
2. Description of the Prior Art
The use of pipeline pigs, and their construction, has long been known in the petroleum industry. Generally, a pipeline pig is a device which is inserted into a pipeline and moved through the pipeline by liquids or gases.
Pipeline pigs are moved through a pipeline for a number of various purposes, such as cleaning the interior wall of the pipeline, separating one fluid component from another, displacing liquids which have condensed in a pipeline used to transport gas, and locating and removing obstructions in the pipeline. To more effectively accomplish these various tasks, different operating implements, such as cups and discs, are employed on a pipeline pig.
Pipeline pigs of the prior art are typically assembled by positioning the cups or other operating implements onto a metal pig body and securing the implements in place with a number of nuts and bolts in combination with several steel plates. While the assembly of a pipeline pig in this manner has generally been accepted by the industry, many inefficiencies are encountered in the use of such pig assemblies. For example, because of the number of parts used to retain the operating implements on the pig body, a relatively substantial amount of time is needed to replace the operating implements. Moreover, the large number of parts used leads to increased materials costs. Finally, the assembly of pipeline pigs as described above results in an inflexible structure which is unable to efficiently pass around corners and past irregularities in the pipeline, and thus has a tendency to get stuck in the pipeline.
The present invention, which is directed to an improved cup and retaining apparatus, overcomes the inherent deficiencies of prior art pipeline pigs; and thus, the present invention represents an advance in the state of the art relating to pipeline pigs.